Headlight relay switch

XJ6c 1977. The headlight relay switch is kaput, I think. I have a new one. The wiring has a clip for each pin, but there is one wire that was added so that two of the pins were linked. It came off, and I am not sure where. Help. Lawrence

A picture is worth a thousand words they say.

Wire colors means everything ! What is the color of the wire in question?


The stalk switch provides ground to operate the relay, Lawrence - blue/black and black wires. In addition; the button on the stalk grounds the washer motor and headlamp wiper relay…

Black wires are straight ground…

xj6 85 Sov Europe (UK/NZ)

This is to Frank, Doug, and Robin. Attached is the bottom side of the headlights relay switch. Note the improvised red wire, which I experimented with by cramming the discopnnected end onto the B post, thus connecting A and B in two ways, through the capacitor
(if that’s what it is) and through the red wire. Should have known better That caused me to lose all lamps.

I was trying to restore the high beams.

I have a new/used relay. Perhaps I could wire it in the manner shown in the diagram with the red wire completely removed.

Also, an independent matter: the dash lights worked until I took it in for an ignition problem, which turned out to be a short somewhere on the passenger side of the engine. After that was fixed I discovered there were no dash lights.

(Attachment Wiring.docx is missing)

Resending diagram

2ndWiring.pdf (91.3 KB)

This is the h/l relay on my S11

Brown +12 unfused
Blue +12 from switch
Blueblack: signal (ground I think) from the stalk for dipping
Bluewhite/Bluered are the outputs to the lamps. They belong together respectively.

It latches from bw to br with blue powered.
With bb grounded (think) it powers the highbeams via brown, which means that when you pull the stalk and have the lights on all 6 should be on, and when you have the lights off (blue unpowered) it will not latch.

A red wire with a capacitor connects across the relay coil in S3s.
Dash-and sidelights and license plate lamps are one circuit, unfused. The dimmer (rheostat) or a bad ground if the sidelights come on.

Use ‘relay’ when talking about the plain relay, Lawrence - ‘switches’ are something else - and it confused me…:slight_smile:

Instead of alphabet it’s safer to use the numbering on the relay’s terminals. And it is important to wire the relay according to the wiring diagram, which refers to those - other connections is plain wrong.

Your initial problem may relate to a faulty relay or indeed wrong connections - and diodes are not shown in my S3 diagram set-up, and should not be required. Replacing the relay with your spare is pertinent - but with connections in doubt; it’s somewhat dubious to copy them on the replaced relay…

Your remark on losing the high beams raises a point. On the main light switch there is a ‘fog’ position, which is standard on ‘European’ cars, but which may have been activated by a PO. This switch position disables the high beam…

Brown (constant power) goes to ‘81a’. Blue/black (to stalk switch) goes to ‘31b’ - blue (from light switch) to ‘56’ - blue/red (low beam) to ‘56b’ and blue/white (high beam) to ‘56b’…

xj6 85 Sov Europe (UK/NZ)

Frank–and all others who have recently messaged me–I am grateful for guidance on the headlamp relay problem. I put in a new one and wired it per instructions. Now the high and low beams work as they should. As for the hazard function (when all four corners
blink) only one works, driver’s side rear. When the headlights are on, all bulbs seem OK. My turn signals, left and right, are OK. And, of course, all of the dash lights have gone to bed–a separate matter I suppose. Lawrence.

To clarify, Lawrence; the turn signal works as it should, with or without the headlights ‘on’, and hazard works only on one external lamp? And the dash warning lamps work as they should in all cases - including hazard…?

Same wiring are used in direction and hazard, but the latter bypass the stalk switch - powering lamps through the hazard switch. Wiring diagram indicates that your symptoms cannot occur…:slight_smile:

However; accessing the hazard switch may clarify - or some ground fault at the lamps. Repeat operation to verify symptoms described…?

xj6 85 Sov Europe (UK/NZ)

Frank, David, Robin, and Doug: I thank you for your offerings. At present, all lights on the outside of the car work–all four hazards with the “hazard” indicator, turn signals (also with interior indicators OK), brights, dims, tail lights, and side lights
. . . I think that’s it. I put in a another relay and fiddled with connections. Now my challenge is: the lights for the instrument panel & gauges don’t work, nor the map light (controlled by a button on the dash), nor the interior light (button right next
to it), and the lights when you open the doors, also kaput, but I don’t really care about that. I had a spark in the back seat area when I put in a wire to run a 12v electric heater (I have it connected directly to the battery, a switch on the positive wire;
I am going to try getting the power from the cigarette lighter). Lawrence

First step is to check fuse #3, Lawrence - it covers most of the items you mention…

Change the fuse, but if the fuse is OK, it may be the fuse holder failing to connect. Sometimes, with high current fuses, the holder may overheat and the wires disconnects…

xj6 85 Sov Europe (UK/NZ)

This forum make my S1 hypochondriac,every desease wrote here come in car…:grinning:

in left side i haven’t a relay like your , this in photo is my lights relay?

thank you.


Fred, it looks like a relay, but I’m quite low on the knowledge scale. You need to put it on the forum that speaks to XJ6 / series l, II, III issues. The best people there reply quickly to my questions. Lawrence


Thanks for the fuse issue. No 3 replaced and my interior light and map light now work, but my instrument/dash lights still dark. I’m wondering about the rheostat, could that be the problem? And would it be OK to bypass it, or is there
in it a necessary resistor function? Lawrence

Mail](https://go.microsoft.com/fwlink/?LinkId=550986) for Windows 10

Lawrence, this is the #xj List. Probably best to start a new thread though.

You can bypass the rheostat but it apparently Helps to have it connected to save your bulbs from voltage spikes or so! Ideally, make a test light. Connect one wire to a good ground and with the other, poke around at the rheostat, the instrument wiring and so on until the lamp lights up (or stops lighting up of course). Then you know what the trouble is. Or at least where.



Wizard Doug, has often posted that many bypass the dash ight rheostat. Mine is dark at the moment,. I did have them working, not that long ago!!

That heater connection may have something to do with the fuse blow!! Spark = short!!!

Do you have and use the S57 jaguar Schematic??

Yes you can definitely bypass it, will also considerably brighten things up.
Check your fuses, if you have a good ground and if the lights get 12V.
Could also be your light switch, IIRC it’s the Red/White cable.